Germinating spores of Streptomyces viridochromogenes release an antibiotic molecule that is an inhibitor of membrane-bound adenosine triphosphatases. This antibiotic acts as a germination inhibitor of the spores and is released during initiation of germination by calcium ions. The chemical identification of the antibiotic is being studied. A major thrust of the research project is aimed at determining the mechanism of ATPase inhibition by the antibiotic and how its release from the target site is predicated by Ca ions. Studies of the biochemical processes involved in sporulation and germination of the organism are to be made with the aim of defining the role of the ATPase inhibitor antibiotic in these processes. A role for this antibiotic in the producing organism has been established and the proposed research is designed to define the mechanisms involved. Studies of the possible role of the antibiotics gentamycin, streptomycin and puromycin in the respective producing organisms will be continued. These studies are at the preliminary stage at present.